Method of operating a reducing furnace



Feb. 5, 1935. y A, J, MASON 1,990,296

Patented Feb. 5, 1935 ME'rnoD: oF

i' ceased 'I'his invention relates to' improvements `-in furnaces and method of operatingthe's'ameand of reducing. The inventionrelatesmore.particularly to afurnace providing a'reducingheat'.

By the `use of my invention IIJ-have madeaznew furnace and also developed a new process or method for operatingthe same and for reducing material under heat. By the use of my invention, I am able to provide a high temperature and a highly reducing atmosphere in'a very economical manner.

Other features and advantages of my invention will appear more fully as I proceed with my specification.

In the accompanying drawing, I have shown a furnace embodying the features of my invention and adapted for carrying out my improved process or method.

In such drawing- Figure 1 is a vertical sectional view, taken as indicated by the line 1 of Fig. 2,; and Fig. 2 is a horizontal sectional view taken as indicated by the line 2 of Fig. 1.

As shown in the drawing, the furnace may include a cylindrical wall l0` madeof suitable refractory material with a bottom 11 and top 12 made of similar material. 13 indicates the interior of the furnace or fire box in which is placed the material 14 to be heated and reduced. 'Ihis material has mixed with it `some suitable substance for furnishing carbon, such as, for example, coke or coal.

15 indicates an annular spiral gutter-like groove in the inner wall of the furnace, the upper end thereof, as indicated by 15a, connecting with an inlet pipe 16 and the lower end thereof 15D issuing into an outlet or discharge pipe 17. The fuel, for example, powdered coal, gas', oil, or the like, mixed with a suitable amount of air, enters through the pipe 16. In operation, it is to be understood that the furnace is brought upto heat in some suitable manner so that the fuel, as it enters the hot furnace, is ignited. The velocity of the,4 entering fuel Vmay be sufficient so that the combustion will not go back into the inlet pipe 16 to. any undesirable extent. The burning fuel follows around in the channel 15 and the productsof combustion pass out through the pipe 17. The downward spiral permits any slag formed from coal or melted ash to follow with the burning fuel and products of combustion and find an exit from the furnace through the pipe 17. It isto be noted that ,the pipes 16 and 17 are oppositely tangentially directed to facilitate the rotary motion of the burning fuel and products of combustionwin thefur-kv nace, asv indicated by the. arrows.

:'I'have found kthat Iin operation, tnezfuei wanaA suitable adrnlxture ofi air is: preferably `causedito enter at .a highv velocity, for example';.'fromzf3000 to 15000.1inear feetia' minute," dependingupon n thediameterzofthe furnace.AV i In operation, the heat from the combustion. of

the fuel is suicient to reduce the material in the furnace. A great part of this heat naturally is radiant heat received from the walls of the furnace which ordinarily are heated to radiance.

The carbon mixed with the material to be reduced causes a formation of carbon monoxide inthe central zone of the furnace. The centrifugal force produced by the rotary motion of the burning fuel lessens or prevents a mixture of the carbon dioxide in the products of fuel combustion with the carbon monoxide in the central zone of the furnace. Carbon dioxide being much heavier than carbon monoxide causes the former to follow the exterior walls while the lighter carbon monoxide is permitted to collect in the central zone and is rlargely retained within that zone,-

constantly revolving, in the form of an eddy, but at a very hightemperature. In this manner, I

succeed in burning the fuel economically, achieve a very high furnace temperature, and still retain within the central zone an atmosphere in which carbonmonoxide predominates over carbon dioxide. For example, I succeed in keeping the proportion of these gases as high as approxil -f mately 9 to 1, provided a proper amount of car-v bon is furnished within the central zone with the material to be reduced.

Also, any carbon monoxide occurring in the products of combustion is more or less separated out from the carbon dioxide by centrifugal force-.

so that such carbon monoxide is concentrated toward the central zone of the furnace to assist in the reducing action whereas the carbon diox-` ide will pass out through the pipe 17.

v It will be observed that -thehighly reducing atmosphere remains constantly within the fur-v avoid scale before forging, for treating phos-l phate rock to disassociate the phosphorus, for

maintaining the burning gases in a'whirling state Y treating iron ore to lmake sponge iron, and the like. Y

I have found that by the use of my inventio f substantially most operationsA which are now ing atmosphere-may be* accomplished in a furnace not'using electricity for heat' 'and in amore economical manner. t

While I have shown and described certain embodiments of my invention, it is` to beunderstood that it Changes, therefore, in the cons tructioncand, ar-v a rangement may be Vmade without departingyfrom the spirit and scope of the invention 'asdisclosed tention to claim all novelty inherent4 in my in# vention as broadly as permissible, in view of the prior art. y c l What I regard as new, and desire to secure by Letters Patent,xis:x- V,

1. The methodofrreducing :byflheat in afurnace, consistingof-'mixing carbon with thema-k te'rial tol be reduced, heating the same withburning fuel caused to revolve above and adjacent the bed of material, said burning fuel being maintained substantially separatefrom said bed, and

is capable of many modiflcationa l, gal force arrelatively high concentration of car- .bon monoxide ,i gas inthe central zone of the c. Y .'.furna'ce-- I l in the appended claims, in which it is my in'- to produce by centrifugal force a relatively high concentration of carbon monoxide in the central zone of the furnace.

2. The method of reducing by heat in a fur nace, consisting of mixing carbon v.with ,y the ma-.

terial to be reduced, heating }the same with'burning fuel to "produce carbon "monoxide from the gases in a whirling state to produce by centrifu- 3. The method ofoperating a reducing furnace heated with burning gases, including the step l of introducing the burning gases tangentiallyjat a relatively high velocity above and adjacent the bed of material, maintaining the burning gases substantially separate fromsaid bed, and main- Y taining thel burning gases in. a whirling `state -to produce by centrifugal forcefa relatively high concentration of carbon `monoxide gas in the central portion lof' said whirling gases.'

Y lAR'KI'HUR'J. MASON. 

